1. Field of the Invention
The invention relates in general to a luminance compensation apparatus and method, and more particularly to a luminance compensation apparatus and method, which directly compensates luminance values of pixels of the multimedia data according to the environment luminance.
2. Description of the Related Art
Referring to FIG. 1, a schematic block diagram of a conventional portable device using a gamma correction unit is shown. The portable device 100, such as a mobile phone or a personal digital assistant (PDA), usually uses a tone reproduction unit 110 (e.g. a gamma correction unit) for performing a tone reproduction-curve mapping (e.g. a gamma-curve mapping) on the input multimedia data Dm, such as image or video data and accordingly outputs corrected multimedia data Dc to the LCD 120 for display. Due to the ‘surround effect’ in a human vision system, the gamma correction unit 110 under-compensates the gamma curve (i.e. end-to-end gamma is about 1.1-1.2) in a dim environment and thus the LCD 120 can provide more subjectively pleasing experience of image/video viewing for a user.
However, the images or videos may be viewed in different environments where lighting conditions are different, and therefore, using the same gamma-curve for correction lacks flexibility and cannot ensure the multimedia data is corrected appropriately. Therefore, it is desirable to have a portable device which can overcome this deficiency.